A wireless network is a flexible data communication medium implemented as an extension for, or as an alternative to, a wired network. By using radio frequency (RF) technology, wireless networks transmit and receive data over air, minimizing the need and the cost typically associated with wired connections. Moreover, wireless networks offer mobility and flexibility for users. For example, doctors and nurses in hospitals are able to use hand-held devices or notebook computers to access patient information from a server through wireless networks without having to search for a physical jack to plug their devices or computers into.
FIG. 1 demonstrates a prior art wireless network configuration. Specifically, the network configuration comprises wireless stations 108 and 110, wireless medium 106 and access points 100, 102 and 104. Wireless stations 108 and 110 communicate with access points 100, 102 and 104 through electromagnetic airwaves 106. Access points 100, 102 and 104 are also connected to wired network 112 and have access to the network resources of wired network 112 such as, server 114, network printer 116 or other devices coupled to wired network 112. It should be noted that wireless stations 108 and 110 are not stationary and do not have to communicate with particular multiple access points. For instance, wireless station 108 may seamlessly move from the coverage area of access point 100 to the coverage area of access point 104 and still maintain its data connections with the access points.
Despite the portability and the convenience that wireless technology offers, there still lacks a comprehensive security scheme to ensure privacy and integrity of the data on wireless networks. For instance, one existing approach is to utilize static keys to encrypt data on a wireless link. Such encrypted data are vulnerable to attack, because the probability of deciphering them is much greater than if the data were encrypted with constantly changing keys. Another approach involves a wireless station sharing a group key with an access point. Thus, when any one device on a wireless network falls into the hands of an attacker, the security of every system in the network is compromised. Yet another approach has every wireless station share one key. As a result, any wireless station is capable of decrypting the traffic of any other wireless.
As has been demonstrated, an improved method and an apparatus are needed to enhance the security of a wireless network.